Compare DVI-I and DVI-D | Important differences

DVI is one of the most common interfaces in the mid-price segment for connecting a computer and a monitor. It is he who can be found on budget and inexpensive video cards, as well as on office and home displays with resolutions up to Full HD inclusive and refresh rates up to 60 Hz.

DVI itself is one of the first digital video transmission standards. Of course, even before him they tried to somehow abandon the analog methods of communication, which have an extremely low bandwidth. But DVI is the most widely used.

And this protocol itself exists in three variations — DVI-A, DVI-D and DVI-I. They differ, among other things, in the number of contacts involved in signal transmission. Let’s figure out what are the main differences and similarities between DVI-I and DVI-D, as well as how Single Link differs from Dual Link.

How DVI works

Despite the fact that DVI is, in principle, a digital interface, which is reflected even in the name, which stands for «Digital Visual Interface», when developing it, the creators decided to achieve compatibility with old monitors. And for these purposes, support for analog data transfer was added to the bus.

The analog data pins are to the right of the 24-pin bus on the digital portion of the package. These are the ones with a «long» «ground» and 4 additional connectors above and below it. On this bus, information about the location of red, blue and green pixels (RGB model) is transmitted in analog form.

The 24-pin main bus is needed for digital data transfer. And, depending on the type of DVI, it can physically consist of a different number of connectors.

So, DVI-I SL and DVI-D SL means connecting 18 pins. And DL — all 24. The DVI-A analog protocol uses mainly «ground» contacts — 12 connectors from the main bus.

After connecting the monitor, the motherboard determines which standard is compatible with this screen. Then the clock frequency, resolution and other operating parameters are adjusted. What is very important, the bandwidth of the DVI interface depends on the length of the cable. The same monitor connected with 2m or 10m wires will have different resolution and refresh rate.

It is also worth noting that there are two ways to connect monitors via the DVI connector — Single Link and Dual Link.

The fact is that the connector is equipped with duplex contacts that duplicate each other. So, he has two red pairs, two blue pairs, two green pairs. Each pair is, in fact, «plus» and «minus».

If the monitor receives data from only one trio of pairs, this is called Single Link (SL). If from two, then already Dual Link (DL).

DL mode doubles the bus bandwidth. And this is necessary to achieve two goals — either double the maximum supported resolution, or also double the refresh rate.

The fact is that the DVI protocol in SL mode works with monitors of a rather low resolution. The maximum supported is 1920×1080 pixels (Full HD). In SL mode, it can be increased many times — for example, up to 2560 × 1600 pixels.

DVI-D interface

DVI-D (Digital Visual Interface — Digital) is an exclusively digital video data transmission interface. It is commonly used in modern monitors and graphics cards due to its low cost and ease of production. Also, developers do not need to achieve compatibility with legacy technologies.

DVI-D can operate in two modes — Single Link and Dual Link. In the first case, the maximum clock frequency is 85 Hz on small (up to SXGA inclusive) screens, in the second — 120 Hz on screens up to WUXGA, including Full HD.

DVI interface

DVI-I (Digital Visual Interface — Integrated) is a digital-analog video signal transmission interface. It adapts itself according to the conditions of use and can switch from digital to analog transmission.

Most often, video cards of the middle price segment are equipped with the DVI-I standard, and immediately in the DL version. Thanks to it, they are able to transmit HD video or stream with an excellent frame rate to any connected monitor or projector.

Because the analog and digital pins are on opposite sides of the connector, they have no effect on each other. And the resolution and clock speed are the same as DVI-D.

Differences and similarities between DVI-I and DVI-D

So, DVI-D is an exclusively digital interface, and DVI-I supports the transmission of both digital and analog signals. Essentially, DVI-D is part of DVI-I.

Let’s compare both options and determine which is better.

It is clear that the only difference between these two interfaces is the presence of contacts for transmitting an analog signal.

Development of standards

However, in modern video cards (produced after about 2013), this connector is practically not found. This is due to a fairly large number of shortcomings. Among them:

1. Increased sensitivity to external electromagnetic fields, which can become a source of interference and noise;

2. Noticeable signal loss with a long cable length (from 2 meters);

3. Poor compatibility with non-standard format screens (such as 32:9);

4. Inability (even in DL) to work at 4K resolution.

Because of all these shortcomings, it began to be gradually abandoned. Moreover, in 2013 HDMI 2.0 was introduced, which brought support for impressively high resolutions. And then DisplayPort came out, which has even more bandwidth and therefore even supports 8K monitors in iteration 1.4 — and can work on top of the USB Type-C connector, which is generally amazing.

New video transmission standards have proven to be more scalable and performant than DVI. And that is why they began to refuse it. At the time of this writing (April 2019), these connectors are extremely rare, and DVI-I is generally only left in “museum” video cards.

Therefore, when assembling a new computer, you should not chase cheapness and the mandatory presence of a DVI connector. At the moment, there are many more productive standards.